BACKGROUND: In 2012, the US experienced 48,277 cases of pertussis, the highest number of reported cases in nearly six decades. Although the Advisory Committee on Immunization Practices expanded its recommendation of the use of tetanus, diphtheria, and acellular pertussis vaccine (Tdap) to all adults in 2012, 17.7% of pertussis cases in 2014 were in adults. We studied the demographic and socioeconomic status characteristics and factors associated with Tdap immunization status.
METHODS: We analyzed data from four states (Georgia, Rhode Island, Tennessee, and Virginia) that experienced an increase in pertussis cases and administered the Behavioral Risk Factor Surveillance System (BRFSS) Tetanus Diphtheria (TDAP) (Adults) module in the year 2014. Tdap vaccination levels were stratified by demographic and socioeconomic status characteristics: age group race/ethnicity, marital status, education attainment, employment status; household income, perceived health status; health insurance status; having a personal healthcare provider; time since last routine checkup; reported cost prevented them from seeing a doctor; influenza vaccination in the last 12 months; and having ever received pneumococcal vaccination. Chi-square tests and multivariable logistic regression were performed to identify factors independently associated with Tdap immunization status.
RESULTS: Tdap immunization coverage was 30.6% (95% CI= 29.4, 31.7) among adults aged ≥18 years. Tdap immunization coverage was significantly higher among adults aged 18–49 years (37.7%) and 50–64 years (29.1%) compared with adults aged ≥65 years (18.6%) (p<0.001). Tdap coverage was significantly lower among non-Hispanic blacks (22.1%) compared with non-Hispanic whites (29.6%) (p<0.001), but was higher for Hispanics (31.1%) and non-Hispanic Asians (31.2%) compared with non-Hispanic whites (p<0.001). Tdap immunization coverage was significantly higher among those who identified as male; never married; higher educational attainment; higher income level; excellent, very good, or good health status; health insurance coverage; reported having a personal healthcare provider; reported having a routine checkup in the previous year; did not report that cost prevented them from seeing a doctor; reported receipt of influenza vaccination in the previous year; and reported having ever received pneumococcal vaccination (p<0.05). Tdap immunization coverage was significantly lower among those who reported being widowed, divorced, or separated and were unemployed or not in the workforce (p<0.05).
CONCLUSIONS: Demographic and socioeconomic status characteristics and risk factors have differential associations with immunization coverage. These findings suggest support the need for immunization strategies that address socioeconomic determinants to achieve health equity in immunization coverage.